Why make your own? Because it'll taste better than any store bought chunky or creamy crap you buy from the store and it's not that hard to do yourself! Or at least, not that hard for an Alton Brown recipe. Just fry peanuts with peanut oil in a wok, let them cool down and then throw them in a food processor. He has his own instructions to add some crunch to it, which let's face it, is the only way to go with peanut butter.